


bramble bush

by momo314



Category: Pocket Monsters: Sword & Shield | Pokemon Sword & Shield Versions
Genre: F/M, First Time, Frottage, Menstruation, Object Insertion, Post-Canon, Sibling Incest, Tampons, Vaginal Fingering, and by object i mean
Language: English
Status: Completed
Published: 2019-12-23
Updated: 2019-12-23
Packaged: 2021-02-18 04:01:07
Rating: Explicit
Warnings: Underage
Chapters: 1
Words: 4,830
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/21921427
Author URL: https://archiveofourown.org/users/momo314/pseuds/momo314
Summary: Marnie has her first period. Previously restrained emotions bubble to the surface in its wake.
Relationships: Nezu | Piers/Mary | Marnie
Comments: 4
Kudos: 70





	bramble bush

**Author's Note:**

> This takes place after the post-game, so Marnie is 14 and Piers is 22~. But (disregarding the implications of a couple lines) you can really imagine them at whatever age you prefer.

"Marnie, you feelin' alright?" Piers knocked on her door lightly. Marnie was usually up and about by the time he rolled out of bed, so he was surprised to see no sign of her around. Had she come down with something during her trip? He cracked open the door and sure thing, there was the bundle wrapped in blankets. "Come on, Marnie. Even if you don't feel well, you should at least get up and eat somethin'..."

No response, just the long, deep breaths of someone thoroughly asleep. With a little sigh, Piers stepped inside. As much as he didn't want to disturb his sister's sleep, the thought of her suffering from some wild Galar illness couldn't escape his mind. Spikemuth's clinic had expanded a lot in the last few years, but if there was a real problem he'd have to take her to the next city as quickly as he could.

Marnie was laying on her side, face buried into her pillow, with her messy hair furled around her head. A bit of her neck was exposed past the covers, so Piers carefully laid the back of his hand against it, trying to judge her temperature. She was a little warm, but he could probably rule out a fever. Still, it was better to hear what was wrong straight from Marnie. Shaking one of her shoulders, he called her name again. "Marnie? Wake up for a bit." A low groan, but no other movement. It was time for more drastic measure. Piers gripped at her bed sheet, pulling it away from her body—and blanched.

There was a large red stain on the sheet, around the size of his palm. It was a bright, vivid red, one that instantly made Piers heart work double time. It was certainly blood—the sharp copper-like scent was heavy in the air now—how the hell hadn't he noticed it before?

His hands were shaking as he finished pulling the covers off Marnie entirely. She was covered in blood. It was soaking through her pajama bottoms. How? What was... He had to get bandages, or something to stop the bleeding. Had Morpeko mistakenly bit her in her sleep, or some bizarre wound opened up in the night? Before Piers knew it, he'd gone dead silent and was going over everything in his head. First thing he had to do was take a look at the wound, staunch the bleeding, take her to the clinic. Piers yanked down Marnie's pants, looking for any sort of wound, and came face to face with his sister's blood-drenched cunt.

He froze instantly in place as the gears started to turn in his head. The blood didn't seem like usual blood, a little too bright, and the metallic scent was off as well. The truth should have come to him once he saw the bleeding concentrated where it was. Marnie was at that age, after all! He'd even given her the talk years ago, when she was 11 and he figured she'd be starting any day now, but she never had. Between the Gym Challenge and everything else going on lately, he'd totally forgotten it was a possibility. As quickly and cautiously as he could, he tried to slip Marnie's pants back on, but all the jostling earlier was too much for Marnie to sleep through.

Her pants were still around her thighs when Marnie looked down at her brother between her legs. The haze of sleep was gone from her face in a second as her eyes went wide, "Bro?! What are you—" Her words cut off when she suddenly saw the rest of the scene and sat up. "Blimey! There's blood everywhere!" Piers was about to blurt out a litany of excuses that all seemed very poor now that he knew the truth, but Marnie at least understood her situation far quickly than he had. "Oh no," she groaned. "Why'd I have to start overnight..."

"Uh... Mornin', Marnie." He practically hopped off her bed, blurting out, "Looks like you finally got your period, eh? I'll go grab you a towel." Marnie nodded and gingerly pulled her pants back up over her hips as Piers left the room. He chose a dark towel from the linen closet, then returned to give it to her so she could clean herself up.

"How 'bout you go get a shower and I'll go grab some stuff for you at the shop. We can get your bed all settled after, alright?" That little downward tug at the corner of Marnie's mouth told him how distressed she was over the rude awakening, but she sullenly nodded again. "Hey." Piers lowered his voice. "Everything's all natural, Marnie. Might seem a little weird to get used to at first, but you shouldn't bug out about it or anythin'. Just... completely normal. Y'know." He was babbling at this point, but at least it was enough to bring a slight smile to Marnie's lips.

"You're the one who's buggin' out, Bro. You think I was dyin' or something?"

Piers awkwardly laughed, but he was relieved that Marnie hadn't misunderstood what he was doing by undressing her. "Maybe a lil bit, yeah."

"D'ya even know what you're gettin'?" she asked.

"Think your big bro can't handle it?" The look Marnie was giving him said as much without a word.

It turned out that there were a lot of choices for menstrual products at the store, and while he'd initially panicked, it was important to be quick and decisive for Marnie's sake. In the end, Piers had picked up a familiar sounding brand of painkillers, a box each of slim looking pads and some overnight ones, and, after some hemming and hawing, a box of tampons. The brief image of Marnie using the applicator had sent such an odd feeling through him that he'd immediately gone with the box of smaller tampons without one instead. It was fine. Once Marnie was all settled she could pick out whatever she wanted anyway.

The shower was still running by the time Piers got back. Made sense that she'd want a long, relaxing soak after what had happened, so he wouldn't get on her for using all the hot water this time. He gave two raps on the door and called out, "Sis, I'm home. I'm gonna bring in the stuff I bought, yeah?"

"Alright."

While the flat was bigger than the one they'd lived in after their parents died, with an extra toilet down the hall, neither of them never bothered locking the bathroom door. Maybe it was just habit after sharing a single bathroom for so long, but Piers had noticed that Marnie still preferred using the main bathroom even when he was in there getting ready, and often he found himself doing the same thing.

So really, he should have been more than used to the sight of his little sister's silhouette in the frosted glass, either turning his eyes away in boredom or distaste. He did neither. It'd been bothering Piers the whole time he was out—the fact that Marnie was becoming an adult. Participating in her Gym Challenge and finally accepting her future place as the next Gym Leader of Spikemuth had made Piers think long and hard about how Marnie was growing up, but this felt like the final nail in the coffin.

It was with those eyes that he couldn't help but stare at her blurred form, looking for the ways it had changed. Her chest had always been small, but now he felt unsure—was there more of a curve there than before? Her hips were wider than he remembered, too, and suddenly Piers was looking at the body of a budding young woman, not the stick-thin little girl he'd carried on his shoulders when he was her age. He immediately shifted his gaze and cleared his throat, setting down the bag on the counter. "Uh... I bought some pads and some... tampons to try, if you want 'em. There's also some pain pills for ya in here."

"Okay," Marnie said, after a moment. Piers couldn't help but wonder if she'd noticed his staring. "Thanks, big Bro."

"No problem. I'd do anything for you, Sis. Just give a yell if you need me." With those words, he left Marnie to her own devices and decided to take on the mess the morning had left behind. First there was the matter of getting as much blood out of the sheets by running cold water over them, then blotting out the blood that had gotten onto the mattress. He was ready to throw the sheets in for a wash cycle when he realized that he hadn't heard the shower running in quite awhile, yet there was no sign of Marnie.

"Hey?" he called through the bathroom door. "You good in there?"

"Y-yeah, sorry. I'm just... tryin' stuff." There was a bit of a tremor in Marnie's voice that made Piers instantly concerned.

"What's wrong? You alright?"

Marnie's exasperation was palpable as she heaved a long sigh. "I'm fine... I just didn't think it'd be so hard to use a friggin' tampon."

"W-well, you don't have to use it if it's not working out for you." While Piers couldn't imagine exactly how it worked, he wanted to be encouraging. "I bought you some pads, too, y'know."

"The pads feel real weird, too! And I'm worried it's just gonna leak everywhere when I move around... But I can't get any tampons to work right either. Just when I think I put it in right, I stand up and it's all I can feel!" Marnie's voice pitched higher, the way it did when she was getting close to her limit. Full-blown meltdowns were rare nowadays, but the stress of her changing body must have been weighing down on her.

"Sorry, Sis. Wish I could help you out somehow." Piers hated knowing Marnie was upset, especially when he couldn't fix things for her. Which was soberingly often, it seemed. The best he could do was be there with her. Maybe he should have asked some of the girls from Team Yell for advice instead of cluelessly trying to take care of Marnie on his own.

Just as Piers started to ask whether he should call someone for her now, Marnie's voice came through. "...Hey, Bro..." Uh-oh. Piers didn't like the way she said that, lilting and hesitant, like she was about to strong-arm him into some ridiculous favor. He liked it even less when she went on, in the same imploring voice, "Could you help me?"

"No way!" Piers could feel his face growing warm as he imagined, in far greater detail than he should have, about what 'helping' Marnie would entail. "I'm not gonna do that!"

"Don't go actin' like you got shame now!" Marnie scoffed back at him. "Weren't ya yankin' off my clothes a bit ago?" Piers sputtered, grasping uselessly for a proper response. "C'mon, Bro. Please? I won't bother you anymore if it doesn't work, but maybe you could do it right..."

Shit. When Marnie asked him so earnestly like that, how could he say no? Even if it was inappropriate to go along with her, the pang of guilt at refusing a rare plea from his little sister was far more present than his conscience insisting that it was a terrible idea. "Tell me you're decent at least," he said.

"Just get in here."

Unsure what to expect, Piers braced himself for the sight of Marnie's naked body when he opened the door. Instead, he saw that Marnie had tied a towel around herself at the chest. Relief flowed through him at first, before he realized that it didn't actually matter when she was sitting with her legs spread wide over the toilet seat. His gaze locked on to the spot between her legs in a matter of milliseconds, watching as she pulled on the end at the string of her tampon. After a second of resistance, the cotton wad stained lightly with blood drew forth, falling free from her cunt.

Piers couldn't say a word. The earlier feelings of trepidation and anxiety returned twice as strong. It was one thing to know how a cunt worked from a theoretical standpoint and to know that his sister had one, and it was another entirely to experience it in these kind of circumstances, the hole gaping and twitching before his eyes. When Piers finally found his voice, it was weak, faltering. "W-w-what... d'ya want me to do exactly?"

"Just... try to push it in for me..." Suddenly Marnie, who had been so gung-ho mere seconds ago with the door shielding her, turned shy.

Piers knew he was the one making it weird, so he quickly nodded his head. It was just a tampon. Just his little sister's growing body. He went to wash his hands in the sink, trying to divorce the act from any kind of sexual context. There was nothing sexual about his little sister's body. He'd seen her all over when she was a little girl, cleaned her up and made sure she was well. Even given her suppositories when it was necessary, and he hadn't felt a thing! Of course that was a long time ago now, but nothing had changed between them. He was still Marnie's big brother. And there was nothing sexual about it. He repeated the mantra in his head as he moved to Marnie's side and dropped to his knees, and she spread his legs for him. Nothing sexual about experimentally rubbing the length of Marnie's cunt and gently pushing the fingertip against the entrance.

"Bro!" she yelped, clamping her thighs together around his hand. Her face was flushed now, looking at him with a mixture of apprehension and something—different, more hesitant, unsure.

"You—" Piers wet his lips, trying to ward off the dryness in his mouth. "You said it was uncomfortable, yeah? I don't wanna... hurt you, so..." His voice trailed off, but Marnie's legs relaxed, and she carefully nodded, letting him continue the exploration. Emboldened by Marnie's show of trust, he reminded himself that there was nothing wrong with what he was doing and gave her a reassuring glance. "I'm just gonna open you up a lil first, before I try insertin' it. Alright?"

"Y-yeah. Warn me first next time is all!" Piers tried again, brushing against Marnie's entrance and slowly, dipping his finger inside.

There was absolutely nothing sexual about him squeezing his finger into Marnie's tight little cunt, nothing erotic about the way her breath hitched, or how hot and wet her insides felt around him. Piers pushed in deeper, gingerly, paying attention to the way Marnie tensed and relaxed. Her breathing was long, quiet, one hand propped against the toilet seat and the other hanging onto the top of her towel. "Does it hurt?" he asked. "Like before?"

"Uh... No. I'm sound. You can try it now. Think I just couldn't get it deep enough..." The apprehension from earlier seemed to have faded from her face, and she was calmer than when she'd called him in. That meant Piers was doing a good job keeping things normal—just a big brother helping out his baby sister, the way he always had. He carefully withdrew his finger, trying to keep in mind how Marnie had felt against him in a purely scholarly way. Which parts tensed and which parts eased up, letting him further in. He had to be delicate about it. Piers opened one of the digital tampons, regretting his earlier reluctance to buy Marnie the kind with an applicator as he settled it on the tip of his finger. He should have just grabbed a box anyway. Then he wouldn't be in this situation...

"Here goes," he said, pushing away the thought for now. Piers eased the tampon past Marnie's entrance, feeling the way she let out a slow breath and wiggled her hips, trying to take it further inside. He pushed it in until he met a soft kind of resistance. Marnie made a sound in her throat, and her hips raised. "Ah, sorry!" Piers rushed out. "Too much?"

"No. It's good. It's... Um..." Marnie bowed her head slightly, pink filling out her cheeks. "It's good." It took a moment for Piers to realize what she meant the second time. Not good as in okay, but good as in— He should have fled once it registered, putting as much distance between him and his little sister as quickly as possible, and then they could pretend that whole situation never even occurred.

What happened instead was the blood rushing straight to Piers's lower half so quickly that it made him dizzy. He pulled his finger out, but Marnie's legs quickly closed around his hand, not so he wouldn't continue this time, but so he wouldn't stop. Something sensible should have left his mouth, something more than the scandalized whisper of "S-sis!" that barely managed to make it out, as though he was afraid of being found out.

"When I saw you this mornin'," Marnie said quietly, "I didn't mind it as much as I should've. And I don't want ya to stop now." Piers could hear his heartbeat in his ears louder than her words—and feel Marnie's pulse, just as rapid, between her thighs. He tried to pull away, but Marnie grabbed his wrist with both hands.

"I... I'm your big brother!" was his weak defense, directed as much to her as it was toward the throbbing in his cock.

"You think I don't know that?" There was a sharp bite to her words, like it was something that had been bubbling for ages at the tip of her tongue, and she could barely stop herself from saying more. Her eyes grew soft, then wet as she admitted, "You're the only one I'd ever trust to touch me like this, Bro. I don't want anyone else."

Piers couldn't believe such a thing to be true. That his little sister had ever had those kind of feelings for her own brother. Why? Since when? What had he done to make her think that way? "Marnie, I'm sorry." The useless apologies spilled from his lips right away. He'd tried hard to raise her right, to be a good big brother, to convince himself that Marnie wasn't lacking even if they didn't have parents. In the end, he'd screwed it all up. It'd been so easy for him to look at Marnie like a woman instead of his little sister just because she'd grown up a bit—what else had he done while she was little to make her think of him in that way? "I don't know what I did to—I messed up. I'm sorry."

"Don't apologize!" Marnie yanked at his hair and pulled him upward so he had to stare into her face. Her eyes were bright with the beginnings of tears, but her expression was twisted in frustration. The anger there faded slowly as she looked at him and hurt crept into her voice. "Do ya really think I'm fucked up, Bro?"

Piers was shocked to hear her say such a thing. "No! It's not like that, Marnie!" Of course she couldn't help but think so, when he reacted like that. He really was a horrible brother. "You're perfect." Marnie's lips pressed into a disbelieving frown, but Piers went on. "I mean it! No matter what. You're the best thing in my life, Sis. I'm just... scared. That I did something wrong, to hurt ya."

"You didn't. You're the best brother I coulda hoped for. That's why I can't help but like you so much. More than anybody."

Those words made Piers's stomach flutter uncontrollably. No matter how wrong it might be, Piers wanted to embrace it, wanted to embrace his little sister in every way he knew he shouldn't. "I love you, too, Sis," he said sincerely. But he knew it wasn't something he could indulge. "That's why I can't let—"

Piers's voice died in his throat as Marnie lunged forward to seal his mouth with a kiss. Clumsy and forceful, but also sweet. He leaned into it despite himself, just barely resisting the urge to return the kiss fully.

The one who broke the contact of their lips was Marnie. Her voice was low, tentative. "If you really feel that way, then... take responsibility, will ya?"

Piers swallowed hard, the taste of Marnie was fresh on his lips, the warmth of her body—the feel of her, inside and out ringing through him like a reverb. It wasn't right, he knew, to let himself be swayed by Marnie's words when she was still so young. Though he'd never consider her a naive child, the gap in their years and experience couldn't be denied. He was an adult, the big brother, her guardian, and he knew better. He knew what was right for her, and that this wasn't it—but when Marnie was asking for it so desperately, he wanted to believe that maybe it was okay. That maybe, if they really loved each other, if they wanted this that much, some sort of allowance could be made for them. "An' how d'ya suppose I do that?" he mumbled, fearful of her response, knowing full well that he'd do whatever she demanded.

Marnie must have felt it, too, the way her face relaxed. She leaned forward to embrace him and pressed her cheek to his, trying to be the one to reassure him now. It worked. After all, the two of them had always had each other's backs when no one else did. As much as he'd done to take care of Marnie, she'd been there to keep him sane, too. Maybe there wasn't any other way they could be, really. Maybe once one of them started feeling this way, it was a chain reaction that swung toward its natural conclusion.

Her answer came at length, but it was firm, more like her usual self. "Keep touchin' me for a start, like you were before." Marnie drew back, seeing if he would try to refuse her again. He couldn't. "Please, Bro." The excitement Piers had tried to bury before came spilling out with her plea. He hid his face, far too overcome, in the crook of her knee and kissed at the softness of her inner thigh, raking his teeth over the pink skin. His hand quickly found its place between Marnie's legs and he sunk his finger into her cunt once more.

Her soft moan of surprise made a perfect harmony with his groan, and there was nothing he could think to block out how good she felt. This time, Marnie was wet from more than blood. She took him in so easily that he immediately wondered how she'd feel around something more substantial. Piers thrust his finger in and out, brushing against the base of her tampon as he stroked the soft walls of her cunt. The moment his finger pressed to a certain spot inside, Marnie made a sound in her throat and told him, "There." Piers didn't need the additional direction to know it was her sweet spot when he could feel her body's reaction. Marnie looked overwhelmed, her mouth wide with uneven breaths as he focused on that area. The nub of her clit was swollen, a tempting sight amid the parted lips of her cunt. There was a split second of hesitation before Piers gave into impulse and pushed his face between her legs.

"B-bro!?" Marnie clutched at the back of his head. Her shocked gasp quickly morphed into a moan as he eagerly licked at her clit. Piers breathed in her warm scent, the lingering bite of iron on his tongue only making her cunt taste sweeter. His hand moved faster, stroking her internally in time with the flicks of his tongue. Marnie leaned back, bucking uncontrollably into his movements, more noises of pleasure falling from her lips in broken fragments. "That, there, Bro, ah!"

Her towel, barely hanging on until now, fell off to reveal the full of Marnie's body. Piers's gaze lavished over her form, noting immediately that he hadn't been mistaken before. Her tits had really grown a little fuller since the last time he'd gotten an eyeful. His breathing matched hers in its intensity, and he watched rapt as she made a face like she was close to crying again. Normally Piers hated seeing her with that expression, but right now, when she was flushed with arousal and unraveling against him—because of him—it was the prettiest thing he'd ever seen. His cock was so hard it hurt when Marnie finally let out a desperate, sharp cry and shuddered against him. Her cunt started pulsing around his finger, sucking in and gripping firmly around the digit. Piers thought he might cream his pants right there, just from imagining how she would feel on his cock.

He pushed down the waistband of his shorts, unable to stand it any longer, and started to stroke himself off. "Oh, oh, Marnie..." Piers was content just to look at her in the aftermath, chest heaving and face dazed, and take his own pleasure, but then Marnie was reaching out for him. Their tongues lashed together as she kissed him hard. Her hand dropped down his chest, moving lower until her small fingers wrapped around his cock. He was so grateful for it he almost sobbed into her mouth. Marnie pumped his cock with crude enthusiasm, but Piers didn't need finesse—he just needed her. Before he knew it, he was rising up onto his feet, pulling apart Marnie's thighs.

"Ah, wait!" Marnie gasped, grabbing at his arms for balance as he moved between her legs.

"I won't, I just want to..." Piers tried to reassure her but it came out in a rush, cut off by a moan he couldn't restrain when he pressed the length of his cock along Marnie's cunt. She felt so soft and red hot against him, his precome slicking her up even further. He clutched at her chest, the urge to feel the sudden softness of her breasts overtaking him, to feel every part of Marnie's developing body with a possessive need.

As if everything wasn't already enough to bring him to the brink, Marnie pressed her hand over his thrusting cock, creating a tunnel between her delicate fingers and her little cunt. It was almost like they were fucking for real, and that thought sent Piers tumbling over the edge shamefully quickly. With a shaking groan and a deep pulse of his cock, he came hard, spilling out his release over Marnie's stomach. His legs turned to jelly just as quickly, and Piers found himself dropping back onto his knees, still reeling from the intense orgasm—better than any he'd ever had before.

Marnie was flushed and breathing hard, she looked down at her pale stomach stained with his come and tentatively dipped her fingers in it. The guilt crept in before the afterglow had even started to fade. What had he done...? All of a sudden, Piers was too afraid to look at Marnie's face, to see her realization that she'd misjudged him all along. That deep inside he'd thought about it sometimes, too, and how that made him way more fucked up than she could ever be. A little begging or tears wasn't enough to make any respectable brother fuck his own sister, not unless he'd wanted to do it in the first place. Marnie was a smart girl. She'd know that for sure. "Sis," he whimpered. "I'm really not any good..."

"Shut up, Bro." Piers's head snapped up at her words. There wasn't any disappointment or regret on her face as she spoke, only love. "I wanna be with you. And I don't think that's wrong. No, I don't give a toss if it is! At least... as long as you think it's alright."

The slight quaver in her voice said it all, that she _needed_ it to be alright with him. She might have started her journey into adulthood, but she was still his baby sister, in need of him and his assurance. And if it was for Marnie, Piers would do anything. Or so that was what he told himself for so long. After this, he couldn't deny that he wanted it just as much as she did.

"Sorry. You're absolutely right, Marnie. Even if the world turns away, we'll have each other." Piers pressed a kiss to her forehead and held her close. "That's the way it's always been for us, yeah?" Marnie slowly relaxed into his arms, but any such comfort was lost on Piers.

He had never wanted that kind of life for her: the two of them against the world. But Piers could feel it now, how much he liked it that way.


End file.
